1. Field of the Invention
This invention pertains to the non-destructive internal and external inspection of produce, including the detection of pits in various stone fruits.
In the area of food processing and production, many stone fruits (e.g., peaches, apricots, cherries, prunes, dates and olives) are mechanically pitted. With the mechanical means available today, complete pit removal does not always occur. Often pits or pit fragments remain in the fruit after they have been through the mechanical pitting device and go undetected through the remainder of the processing stage. This could result in damage to equipment or an unwanted pit in the end product resulting in injury or death to persons.
The problem of pit detection has plagued food processors for many years and has resulted in the expenditure of large amounts of money in the replacement of equipment (slicers, dicers, etc.) which have been destroyed due to undetected pits and fragments. With regard to undetected pits in the end product, processors and insurance companies have faced the problem of product liability claims from injuries to the consumer. As a result, the industry has sought accurate and reliable means to detect and reject fruit which still contains pits or pit fragments after the fruit is mechanically pitted.
2. Description of the Background Art
Several types of automated devices have been developed to inspect produce for certain characteristics. For example, U.S. Pat. No. 3,467,254 issued to Simmons on Sept. 16, 1969, describes an apparatus for detecting pits or remnants in split peaches. U.S. Pat. No. 3,005,549 issued to Flanders et al. on Oct. 24, 1961, describes peach pit fragmentation detection means and techniques for peach halves. Both of these inventions require the fruit to be split in half before inspection, and further require specific orientation of the fruit in the apparatus. These inventions are directed to detecting pits and fragments in large fruits such as peaches, but not in smaller fruits such as cherries or olives or where the processor desires the fruit to remain whole.
U.S. Pat. No. 3,385,434 issued to Nelson on May 28, 1968, describes an apparatus for classifying objects according to their internal structure using light beams. This invention uses light beams to view the interior structure of kernels of corn and sort the kernels according to different interior colors, but would not distinguish between a pit in an article of fruit or some other type of variation in internal structure.
An apparatus for detecting seeds in small fruit such as cherries is described in U.S. Pat. No. 3,275,136 issued to Allen et al. on Sept. 27, 1966. In this invention, the pit must be positioned substantially in line with a light source thus making detection difficult if the pit is off center within the fruit or the fruit is irregularly shaped. Variations in size of the fruit could also make detection difficult.
U.S. Pat. No. 3,768,645 issued to Conway et al. on Oct. 30, 1973, describes a method and apparatus for evaluating articles of produce on the basis of their uniformity and non-uniformity to their transparency to x-rays. U.S. Pat. No. 3,930,994 issued to Conway et al. on Jan. 6, 1976, describes a method and apparatus similar to U.S. Pat. No. 3,768,645, but using light rays. In these inventions, the fruit must be preoriented which can make high speed evaluation difficult.
U.S. Pat. No. 4,534,470 issued to Mills on Aug. 13, 1985, shows an apparatus and method for processing and sorting fruit as a function of color, blemish, size, shape and other variables by uniformly illuminating the entire surface of the article. The invention does not detect light transmitted through the fruit which would be necessary for detection of a pit or internal abnormalities.
U.S. Pat. No. 4,666,045 issued to Gillespie et al. on May 19, 1987, describes an apparatus and method for detecting the presence of pits or pit fragments in fruit by subjecting the fruit to an optical scanning beam as the fruit passes through an inspection zone. With this invention, the fruit is scanned in only one dimension with a single sweeping scanning beam which could make detection difficult if the pit or pit fragment is not centered in the fruit or attaches to the external surface of the fruit after pitting. In addition, lack of symmetry of shape or discolorations or abnormalities on the surface of the fruit could be mistaken for a pit or cause pits to go undetected. Also, the physical size of the apparatus is impractical for commercial use.
U.S. Pat. No. 4,279,346 issued to McClure et al. on July 21, 1981, discloses a high speed asynchronous fruit sorter for sorting various types of fruits according to their maturity using optical density. However, this apparatus will not detect pits or pit fragments in fruit.
U.S. Pat. No. 4,555,633 issued to Bjorkelund on Nov. 26, 1985, discloses a method and device for measuring the presence and size of an object, such as a log, in a measuring zone based on intersecting light beams transmitted toward the object and the amount of light block by the object. Pit detection in fruit is not disclosed in this patent.
U.S. Pat. No. 4,825,068 issued to Suzuki et al. on Apr. 25, 1989, discloses a method and apparatus for inspecting the external appearance of articles such as fruit by reflecting images on four different side surfaces of the article, sensing the reflected images with a camera, and processing the photographed images to inspect form, size and surface conditions of the article. This patent does not disclose detection of pits in fruit.
Although the foregoing patents address some of the various needs of the industry, the devices and methods disclosed in those patents have certain sensitivities to size, shape, color, and orientation of the article of produce being inspected which my invention overcomes. Furthermore, fruit which contains pits which are off-center or pits which remain attached to the surface of the fruit after pitting can pose pit detection errors for the devices disclosed in the aforesaid patents.
The foregoing patents reflect the state of the art of which the applicant is aware and are tendered with the view toward discharging applicant's acknowledged duty of candor in disclosing information which may be pertinent in the examination of this application. It is respectfully stipulated, however, that none of these patents teach or render obvious, singly or when considered in combination, applicant's claimed invention.